I don't use anything else instead. That's why I think it daily. I didn't choose to use it, I'm just the developer responsible for the integrations.
To be fair, I don't do a lot with the GUI, I mainly interface with the API.
I daily think the API documentation is built by one team, the API implementation is built by another team, and a third team uses/tests the API. And NONE of them have ever talked to each other. Or maybe one of those teams is missing altogether? That's the only way to explain how their API got to be what it is.